US20120155133A1 - Direct current/ direct current converter for reducing switching loss, wireless power receiver including direct current/ direct current converter - Google Patents
Direct current/ direct current converter for reducing switching loss, wireless power receiver including direct current/ direct current converter Download PDFInfo
- Publication number
- US20120155133A1 US20120155133A1 US13/329,891 US201113329891A US2012155133A1 US 20120155133 A1 US20120155133 A1 US 20120155133A1 US 201113329891 A US201113329891 A US 201113329891A US 2012155133 A1 US2012155133 A1 US 2012155133A1
- Authority
- US
- United States
- Prior art keywords
- turn
- voltage
- current
- frequency
- period
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
- H02J50/50—Circuit arrangements or systems for wireless supply or distribution of electric power using additional energy repeaters between transmitting devices and receiving devices
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
- H02J50/10—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
- H02J50/12—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling of the resonant type
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
- H02M3/1588—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load comprising at least one synchronous rectifier element
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
Definitions
- the following description relates to a direct current-direct current (DC/DC) converter for use in a wireless power receiver.
- DC/DC direct current-direct current
- Direct current-direct current (DC/DC) converters are generally used in wireless power transmission systems, portable multimedia devices, and/or the like. They may be configured to receive a DC voltage and then may raise or reduce the voltage to a voltage of a stable level requested by an output unit.
- an input unit may provide the output unit with a voltage that is requested by the output unit and thus, an efficiency of the DC/DC converter may approach 100%.
- the efficiency of DC/DC converter may be reduced for many reasons including a switching loss and a conduction loss.
- the switching loss may occur, for instance when a transistor that corresponds to a switch and that is included in the DC/DC converter is turned on, and the conduction loss may occur due to a parasitic resistance of the transistor and a parasitic resistance of an inductor inside the DC/DC converter. While the switching loss may be assumed to be a constant value (regardless of a magnitude of an inputted current), the conduction loss may be proportional to the inputted current. Thus, when a low current is inputted, a component of the switching loss may be higher than a component of the conduction loss, and efficiency may decrease.
- a direct current-direct current (DC/DC) converter for use in a wireless power receiver may include: a voltage converting unit configured to convert, DC voltage, to a predetermined DC voltage; a turn-on switch configured to control current flow of the DC voltage through the voltage converting unit; and a switching controller configured to: detect an amount of current of the voltage converting unit based on a first turn-on period of the turn-on switch, set a second turn-on period of the turn-on switch based on the detected amount of current, and control the turn-on switch based on the second turn-on period.
- DC/DC direct current-direct current
- the amount of current of the voltage converting unit may comprise an amount of current inputted to the voltage converting unit or an amount of current outputted from the voltage converting unit.
- the switching controller may be configured to set the second turn-on period to be shorter when the detected amount of current is less than or equal to the predetermined reference value.
- the switching controller may be configured to set the second turn-on period to be longer when the detected amount of current is greater than or equal to the predetermined reference.
- the switching controller may include: a voltage divider configured to divide, in a predetermined ratio, a voltage outputted from the voltage converting unit; an error amplifier configured to amplify and output a difference value between an output voltage of the voltage divider and a predetermined reference voltage; a first comparator configured to compare the output of the error amplifier with a ramp signal, to output a pulse width modulator (PWM) signal to be used for switching the turn-on switch; a controller configured to set the second turn-on period based on the PWM signal, and to control the turn-on switch based on the second turn-on period; a current detecting unit configured to detect the amount of current of the voltage converting unit based on the first turn-on period of the turn-on switch, and to generate a frequency control signal that controls a frequency of the ramp signal based on the detected amount of current; and a generator configured to control the frequency of the ramp signal based on the frequency control signal, and to output the ramp signal having a changed frequency to the first comparator.
- PWM pulse width modul
- the current detecting unit may include: an electric charge pump configured to output electric charges during a turn-on time where the turn-on switch is turned on based on a turn-on period; a capacitor configured to be charged with electric charges outputted from the electric charge pump during the turn-on time based on the turn-on period, and to discharge electric charges during a turn-off time based on the turn-on period, to output a current measurement voltage; a second comparator configured to compare a current measurement reference voltage with the current measurement voltage; and a controller configured to output a frequency control signal that increases the frequency of the ramp signal when the comparison of the second comparator indicates that the current measurement voltage is greater than the current measurement reference voltage, and to output a frequency control signal that decreases the frequency of the ramp signal when the comparison of the second comparator indicates that the current measurement voltage is less than the current measurement reference voltage.
- the second comparator may include a hysteresis comparator that is configured to compare the current measurement voltage with a high-reference voltage or with a low-reference voltage; and the frequency controller may be configured to output a frequency control signal that increases the frequency of the ramp signal when the current measurement voltage is greater than the high-reference voltage, and to output a frequency control signal that decreases the frequency of the ramp signal when the current measurement voltage is less than the low-reference voltage.
- a wireless power receiver may include: a target resonator configured to receive electromagnetic energy from a source resonator; a rectifier configured to rectify an alternating current (AC) signal received from the target resonator, to generate a direct current (DC) signal; and a DC/DC converter configured to adjust a signal level of the DC signal, to output a rated voltage, the DC/DC converter comprises: a voltage converting unit configured to convert, DC voltage, to a predetermined DC voltage; a turn-on switch configured to control current flow of the DC voltage through the voltage converting unit; and a switching controller configured to: detect an amount of current of the voltage converting unit based on a first turn-on period of the turn-on switch, set a second turn-on period of the turn-on switch based on the detected amount of current, and control the turn-on switch based on the second turn-on period.
- AC alternating current
- DC direct current
- a method for converting direct current to direct current may include: converting, DC voltage, to a predetermined DC voltage; controlling current flow of the DC voltage via a turn-on switch; detecting an amount of current based on a first turn-on period on the turn-on switch; and setting a second turn-on period of the turn-on switch based on the detected amount of current.
- FIG. 1 is a diagram illustrating a wireless power transmission system.
- FIG. 2 is a diagram illustrating a direct current-direct current (DC/DC) converter that reduces a switching loss.
- FIG. 3 is a diagram illustrating a current detecting unit in a DC/DC converter.
- FIG. 4 is a diagram illustrating a main timing of a DC/DC converter.
- FIG. 5 is a diagram illustrating a case where a current measurement voltage V C is less than low-reference voltage in a current detecting unit of a DC/DC converter.
- FIG. 6 is a diagram illustrating a case where a current measurement voltage V C is greater than a high-reference voltage in a current detecting unit of a DC/DC converter.
- FIGS. 7 through 13 are diagrams illustrating a resonator structure.
- FIG. 14 is a diagram illustrating one equivalent circuit of a resonator for wireless power transmission of FIG. 7 .
- FIG. 1 illustrates a wireless power transmission system.
- wireless power transmitted may be resonance power.
- the wireless power transmission system may have a source-target structure including a source and a target.
- the wireless power transmission system may include a resonance power transmitter 110 corresponding to the source and a resonance power receiver 120 corresponding to the target.
- the resonance power transmitter 110 may include a source unit 111 and a source resonator 115 .
- the source unit 111 may be configured to receive energy from an external voltage supplier to generate a resonance power.
- the resonance power transmitter 110 may further include a matching control 113 to perform resonance frequency or impedance matching.
- the source unit 111 may include an alternating current (AC)-to-AC (AC/AC) converter, an AC-to-direct current (DC) (AC/DC) converter, and/or a (DC/AC) inverter.
- the AC/AC converter may be configured to adjust, to a desired level, a signal level of an AC signal input from an external device.
- the AC/DC converter may output a DC voltage at a predetermined level by rectifying an AC signal output from the AC/AC converter.
- the DC/AC inverter may be configured to generate an AC signal (e.g., in a band of a few megahertz (MHz) to tens of MHz) by quickly switching a DC voltage output from the AC/DC converter.
- MHz megahertz
- the matching control 113 may be configured to set at least a resonance bandwidth of the source resonator 115 , an impedance matching frequency of the source resonator 115 , or both.
- the matching control 113 may include at least one of a source resonance bandwidth setting unit and a source matching frequency setting unit.
- the source resonance bandwidth setting unit may set the resonance bandwidth of the source resonator 115 .
- the source matching frequency setting unit may set the impedance matching frequency of the source resonator 115 .
- a Q-factor of the source resonator 115 may be determined based on setting of the resonance bandwidth of the source resonator 115 or setting of the impedance matching frequency of the source resonator 115 .
- the source resonator 115 may be configured to transfer electromagnetic energy to a target resonator 121 .
- the source resonator 115 may transfer the resonance power to the resonance power receiver 120 through magnetic coupling 101 with the target resonator 121 .
- the source resonator 115 may be configured to resonate within the set resonance bandwidth.
- the resonance power receiver 120 may include the target resonator 121 , a matching control 123 to perform resonance frequency or impedance matching, and a target unit 125 to transfer the received resonance power to a device or a load.
- the target resonator 121 may be configured to receive the electromagnetic energy from the source resonator 115 .
- the target resonator 121 may be configured to resonate within the set resonance bandwidth.
- the matching control 123 may set at least one of a resonance bandwidth of the target resonator 121 and an impedance matching frequency of the target resonator 121 .
- the matching control 123 may include at least one of a target resonance bandwidth setting unit and a target matching frequency setting unit.
- the target resonance bandwidth setting unit may set the resonance bandwidth of the target resonator 121 .
- the target matching frequency setting unit may be configured to set the impedance matching frequency of the target resonator 121 .
- a Q-factor of the target resonator 121 may be determined based on setting of the resonance bandwidth of the target resonator 121 or setting of the impedance matching frequency of the target resonator 121 .
- the target unit 125 may be configured to transfer the received resonance power to the load.
- the target unit 125 may include an AC/DC converter and a DC/DC converter.
- the AC/DC converter may generate a DC voltage by rectifying an AC signal transmitted from the source resonator 115 to the target resonator 121 .
- the DC/DC converter may supply a rated voltage to a device or the load by adjusting a voltage level of the DC voltage.
- the AC/DC converter may be configured as an active rectifier utilizing a delay locked loop.
- the source resonator 115 and the target resonator 121 may be configured in a helix coil structured resonator, a spiral coil structured resonator, a meta-structured resonator, or the like.
- controlling the Q-factor may include setting the resonance bandwidth of the source resonator 115 and the resonance bandwidth of the target resonator 121 , and transferring the electromagnetic energy from the source resonator 115 to the target resonator 121 through magnetic coupling 101 between the source resonator 115 and the target resonator 121 .
- the resonance bandwidth of the source resonator 115 may be set to be wider or narrower than the resonance bandwidth of the target resonator 121 in some instances.
- an unbalanced relationship between a BW-factor of the source resonator 115 and a BW-factor of the target resonator 121 may be maintained by setting the resonance bandwidth of the source resonator 115 to be wider or narrower than the resonance bandwidth of the target resonator 121 .
- the resonance bandwidth may be an important factor.
- Q-factor e.g., considering all of a change in a distance between the source resonator 115 and the target resonator 121 , a change in the resonance impedance, impedance mismatching, a reflected signal, and/or the like
- Qt may have an inverse-proportional relationship with the resonance bandwidth, as given by Equation 1.
- Equation 1 f 0 denotes a central frequency, ⁇ f denotes a change in a bandwidth, ⁇ S,D denotes a reflection loss between the source resonator 115 and the target resonator 121 , BW S denotes the resonance bandwidth of the source resonator 115 , and BW D denotes the resonance bandwidth of the target resonator 121 .
- the BW-factor may indicate either 1/BW S or 1/BW D .
- impedance mismatching between the source resonator 115 and the target resonator 121 may occur.
- the impedance mismatching may be a direct cause in decreasing an efficiency of power transfer.
- the matching control 113 may be configured to determine the impedance mismatching has occurred, and may perform impedance matching.
- the matching control 113 may change a resonance frequency by detecting a resonance point through a waveform analysis of the reflected wave.
- the matching control 113 may determine, as the resonance frequency, a frequency having a minimum amplitude in the waveform of the reflected wave.
- the source resonator 115 and/or the target resonator 121 in FIG. 1 may have a resonator structure illustrated in FIGS. 7 through 14 .
- FIG. 2 illustrates a DC/DC converter 200 that reduces a switching loss.
- the DC/DC converter 200 may include a voltage converting unit 220 that converts a voltage of a DC signal V IN received from a voltage source 210 to a predetermined DC voltage V OUT .
- the predetermined DC voltage V OUT may be provided to a load 230 .
- the DC/DC converter 200 may also include a switching controller 240 that controls the voltage converting unit 220 . This may include turning on and off the voltage converting unit 220 is some embodiments.
- the voltage converting unit 220 may be configured to convert the voltage of the DC signal provided when a current flows through a turn-on switch 222 , to the predetermined DC voltage V OUT .
- the voltage converting unit 220 may include the turn-on switch 222 , a second switch 224 , an inductor 226 , and a capacitor 228 .
- the turn-on switch 222 may be a switch configured to be turned on based on a switching signal V P of the switching controller 240 so as to enable the DC current received from the voltage source 210 to flow through the turn-on switch 222 , to provide the DC current I L to the inductor 226 .
- the second switch 224 may be a switch that operates in reverse to the turn-on switch 222 , and may be turned on when the turn-on switch 222 is turned off, based on a switching signal V N of the switching controller 240 . When the second switch 224 is turned on, the second switch may be grounded to an input of the inductor 226 , for instance.
- the inductor 226 and the capacitor 228 may receive the DC current via the turn-on switch 222 , may be charged with the received DC current, and may output a DC of the predetermined voltage V OUT .
- the turn-on switch 22 may include a p-channel metal-oxide semiconductor (PMOS) transistor M P
- the second switch 224 may include a similar transistor M N .
- the switches or switch elements of the switching device may include various electromechanical switches (e.g., contact, toggle, knife, tilt, or the like) or electrical switches (e.g., solenoid, relays, or solid-state elements such as a transistor switch, silicon-controlled rectifier or a triac).
- the switch may be configured to activate.
- the switches may select between ON and OFF positions, which permit and prevent the flow of electricity (power), respectively. Accordingly, the switches control may control electrical connection.
- the switching controller 240 may detect an amount of current of the voltage converting unit 220 based on a first turn-on period indicating a turn-on period of the turn-on switch 222 at a current point in time.
- the switching controller 240 may set a second turn-on period indicating a turn-on period that is to be applied to the turn-on switch 222 based on the detected amount of current, and may control the turn-on switch 222 based on the second turn-on period.
- the amount of current of the voltage converting unit 220 may be an amount of current inputted to the voltage converting unit 220 or an amount of current outputted from the voltage converting unit 220 .
- the switching controller 240 may be configured to set the second turn-on period to be shorter when the amount of current of the voltage converting unit 220 is less than or equal to the predetermined reference value.
- the switching controller 240 may set the second turn-on period to be longer when the amount of current of the voltage converting unit 220 is greater than or equal to the predetermined reference value.
- the switching controller 240 may include a voltage divider 243 , a reference voltage source 244 , an error amplifier 245 , a capacitor 246 , a comparator 247 , a controller 248 , a generator 249 , and a current detecting unit 250 .
- the voltage divider 243 may be configured to divide a voltage outputted from the voltage converting unit 220 .
- the voltage may be divided in a predetermined ratio using two resistors 241 (R 1 ) and 242 (R 2 ), and may output the divided voltage to the error amplifier 245 .
- the error amplifier (EA) 245 may be configured to amplify and output a difference value between the output voltage of the voltage divider 243 and a predetermined reference voltage V REF outputted from the reference voltage source 244 .
- the capacitor 246 may be charged with the output voltage of the error amplifier 245 , and may remove noise.
- the comparator (COMP) 247 may compare the output of the error amplifier 245 that passes through the capacitor 246 with a ramp signal V RAMP outputted from the generator 249 , and may output a pulse width modulator (PWM) signal to be used for switching the turn-on switch 222 .
- PWM pulse width modulator
- the controller 248 may be configured to set the second turn-on period to be applied to the turn-on switch 222 , based on the PWM signal outputted from the comparator 247 , and may control the turn-on switch 222 based on the second turn-on period.
- the current detecting unit 250 may be configured to detect an amount of current of the voltage converting unit 220 based on the first turn-on period of the turn-on switch 222 , and may generate a frequency control signal that can be used to control a frequency of the ramp signal V RAMP based on the detected amount of current of the voltage converting unit 220 .
- the generator 249 may be configured to control the frequency of the ramp signal V RAMP based on the frequency control signal received from the current detecting unit 250 , and may output the ramp signal V RAMP having the changed frequency to the comparator 247 .
- the generator 249 may be configured to output a clock timing signal ⁇ CLK to the controller 248 based on the frequency control signal received from the current detecting unit 250 .
- FIG. 3 illustrates a current detecting unit in a DC/DC converter.
- the current detecting unit 250 of FIG. 2 may include an electric charge pump 310 , a capacitor 320 , a comparator 330 , and a frequency controller 340 .
- the electric charge pump 310 may be configured to output electric charges during a turn-on time t ON where the turn-on switch 222 is turned on based on a turn-on period T.
- the electric charge pump 310 may be configured to include a current source 312 , a first switch 314 , and a second switch 316 .
- the current source 312 may output a predetermined amount of electric charge.
- the first switch 314 may output electric charges during the turn-on time t ON where the turn-on switch 222 is turned on based on the turn-on period.
- the second switch 316 may be grounded and may operate in reverse to the first switch 314 .
- the capacitor 320 may be charged with the electric charges outputted from the electric charge pump 310 based on the turn-on period of the turn-on switch 222 , and may discharge electric charges during a turn-off time based on the turn-on period, to output a current measurement voltage to be used for measuring an amount of current.
- the comparator 330 may be configured to compare a current measurement reference voltage (e.g., V REF — H or V REF — L as discussed below) with the current measurement voltage outputted from the capacitor 320 , and may transmit a result of the comparison to the frequency controller 340 .
- a current measurement reference voltage e.g., V REF — H or V REF — L as discussed below
- the frequency controller 340 may be configured to output a frequency control signal that increases a frequency of a ramp signal when the current measurement voltage is greater than a current measurement reference voltage, and may output a frequency control signal that decreases the frequency of the ramp signal when the current measurement voltage is less than the current measurement reference voltage.
- the frequency controller 340 may output the frequency control signal by classifying the frequency of the ramp signal as a reference frequency, 1 ⁇ 2 reference frequency, 1 ⁇ 4 reference frequency, and 1 ⁇ 8 reference frequency.
- the turn-on switch 222 may be more frequently turned on and turned off.
- the turn-on switch 222 may be less frequently turned on and turned off.
- FIG. 4 illustrates a main timing of a DC/DC converter.
- FIG. 4 shows waveforms for the clock timing signal ⁇ CLK the switching signal V P input to the turn-on switch 222 , the switching signal V N input to the second switch 224 , the current I L of the inductor 226 , and a current measurement voltage V C that is outputted from the capacitor 320 of the current detecting unit 250 over corresponding times periods.
- the current measurement voltage V C may be similar to a waveform of a current I L outputted from the inductor 226 .
- the current detecting unit 250 may be configured to estimate a magnitude of a peak of the current I L of the inductor 226 without (directly) sensing the current I L of the inductor 226 , for instance.
- a turn-on time of the turn-on switch 222 decreases and thus, the peak of the current I L of the inductor 226 and a peak of the current measurement voltage V C may decrease.
- the comparator 330 may be configured to compare the current measurement voltage V C with two reference voltages: a high-reference voltage (VREF_H) or a low-reference voltage (VREF_L).
- the comparator 330 may be a hysteresis comparator.
- the frequency controller 340 may determine that the amount of current is insufficient for a current frequency.
- FIG. 5 illustrates when a current measurement voltage V C is less than VREF_L in a current detecting unit of a DC/DC converter.
- the frequency controller 340 may output a frequency control signal that decreases a frequency of a ramp signal.
- the frequency controller 340 may determine that the amount of current is excessive for a current frequency.
- FIG. 6 illustrates a case where a current measurement voltage V C is greater than VREF_H in a current detecting unit of a DC/DC converter.
- the frequency controller 340 may output a frequency control signal that increases a frequency of a ramp signal.
- the source resonator and/or the target resonator of the wireless power transmission system may be configured as a helix coil structured resonator, a spiral coil structured resonator, a meta-structured resonator, or the like.
- One or more of the materials of the embodiment disclosed herein may be metamaterials.
- RHMs right handed materials
- Metamaterials may be classified into an epsilon negative (ENG) material, a mu negative (MNG) material, a double negative (DNG) material, a negative refractive index (NRI) material, a left-handed (LH) material, and the like, based on a sign of the corresponding permittivity or magnetic permeability.
- ENG epsilon negative
- MNG mu negative
- DNG double negative
- NRI negative refractive index
- LH left-handed
- the magnetic permeability may indicate a ratio between a magnetic flux density occurring with respect to a given magnetic field in a corresponding material and a magnetic flux density occurring with respect to the given magnetic field in a vacuum state.
- the permittivity indicates a ratio between an electric flux density, occurring with respect to a given electric field in a corresponding material, and an electric flux density, occurring with respect to the given electric field, in a vacuum state.
- the magnetic permeability and the permittivity in some embodiments, may be used to determine a propagation constant of a corresponding material in a given frequency or a given wavelength.
- An electromagnetic characteristic of the corresponding material may be determined based on the magnetic permeability and the permittivity.
- the metamaterial may be easily disposed in a resonance state without significant material size changes. This may be practical for a relatively large wavelength area or a relatively low frequency area, for instance.
- FIG. 7 illustrates a resonator 700 having a two-dimensional (2D) structure.
- the resonator 700 having the 2D structure may include a transmission line, a capacitor 720 , a matcher 730 , and conductors 741 and 742 .
- the transmission line may include, for instance, a first signal conducting portion 711 , a second signal conducting portion 712 , and a ground conducting portion 713 .
- the capacitor 720 may be inserted or otherwise positioned in series between the first signal conducting portion 711 and the second signal conducting portion 712 so that an electric field may be confined within the capacitor 720 .
- the transmission line may include at least one conductor in an upper portion of the transmission line, and may also include at least one conductor in a lower portion of the transmission line. A current may flow through the at least one conductor disposed in the upper portion of the transmission line and the at least one conductor disposed in the lower portion of the transmission may be electrically grounded.
- the resonator 700 may be configured to have a generally 2D structure.
- the transmission line may include the first signal conducting portion 711 and the second signal conducting portion 712 in the upper portion of the transmission line, and may include the ground conducting portion 713 in the lower portion of the transmission line. As shown, the first signal conducting portion 711 and the second signal conducting portion 712 may be disposed to face the ground conducting portion 713 with current flowing through the first signal conducting portion 711 and the second signal conducting portion 712 .
- one end of the first signal conducting portion 711 may be electrically connected (i.e., shorted) to a conductor 742 , and another end of the first signal conducting portion 711 may be connected to the capacitor 720 .
- one end of the second signal conducting portion 712 may be grounded to the conductor 741 , and another end of the second signal conducting portion 712 may be connected to the capacitor 720 .
- the first signal conducting portion 711 , the second signal conducting portion 712 , the ground conducting portion 713 , and the conductors 741 and 742 may be connected to each other, such that the resonator 700 may have an electrically “closed-loop structure.”
- the term “closed-loop structure” as used herein, may include a polygonal structure, for example, a circular structure, a rectangular structure, or the like that is electrically closed.
- the capacitor 720 may be inserted into an intermediate portion of the transmission line.
- the capacitor 720 may be inserted into a space between the first signal conducting portion 711 and the second signal conducting portion 712 .
- the capacitor 720 may be configured, in some instances, as a lumped element, a distributed element, or the like.
- a distributed capacitor may be configured as a distributed element and may include zigzagged conductor lines and a dielectric material having a relatively high permittivity between the zigzagged conductor lines.
- the resonator 700 When the capacitor 720 is inserted into the transmission line, the resonator 700 may have a property of a metamaterial, as discussed above. For example, the resonator 700 may have a negative magnetic permeability due to the capacitance of the capacitor 720 . If so, the resonator 700 may be referred to as a mu negative (MNG) resonator. Various criteria may be applied to determine the capacitance of the capacitor 720 .
- MNG mu negative
- the various criteria for enabling the resonator 700 to have the characteristic of the metamaterial may include one or more of the following: a criterion for enabling the resonator 700 to have a negative magnetic permeability in a target frequency, a criterion for enabling the resonator 700 to have a zeroth order resonance characteristic in the target frequency, or the like.
- the resonator 700 also referred to as the MNG resonator 700 , may also have a zeroth order resonance characteristic (i.e., having, as a resonance frequency, a frequency when a propagation constant is “0”). If the resonator 700 has the zeroth order resonance characteristic, the resonance frequency may be independent with respect to a physical size of the MNG resonator 700 . Moreover, by appropriately designing the capacitor 720 , the MNG resonator 700 may sufficiently change the resonance frequency without substantially changing the physical size of the MNG resonator 700 may not be changed.
- a zeroth order resonance characteristic i.e., having, as a resonance frequency, a frequency when a propagation constant is “0”. If the resonator 700 has the zeroth order resonance characteristic, the resonance frequency may be independent with respect to a physical size of the MNG resonator 700 . Moreover, by appropriately designing the capacitor 720 , the MNG resonator 700 may sufficiently change the resonance frequency without substantially changing the physical size of the MNG
- the electric field may be concentrated on the capacitor 720 inserted into the transmission line. Accordingly, due to the capacitor 720 , the magnetic field may become dominant in the near field.
- the MNG resonator 700 may have a relatively high Q-factor using the capacitor 720 of the lumped element. Thus, it may be possible to enhance power transmission efficiency.
- the Q-factor indicates a level of an ohmic loss or a ratio of a reactance with respect to a resistance in the wireless power transmission. The efficiency of the wireless power transmission may increase according to an increase in the Q-factor.
- the MNG resonator 700 may include a matcher 730 for impedance-matching.
- the matcher 730 may be configured to appropriately determine and adjust the strength of a magnetic field of the MNG resonator 700 , for instance.
- current may flow in the MNG resonator 700 via a connector, or may flow out from the MNG resonator 700 via the connector.
- the connector may be connected to the ground conducting portion 713 or the matcher 730 . In some instances, power may be transferred through coupling without using a physical connection between the connector and the ground conducting portion 713 or the matcher 730 .
- the matcher 730 may be positioned within the loop formed by the loop structure of the resonator 700 .
- the matcher 730 may adjust the impedance of the resonator 700 by changing the physical shape of the matcher 730 .
- the matcher 730 may include the conductor 731 for the impedance-matching positioned in a location that is separate from the ground conducting portion 713 by a distance h. Accordingly, the impedance of the resonator 700 may be changed by adjusting the distance h.
- a controller may be provided to control the matcher 730 which generates and transmits a control signal to the matcher 730 directing the matcher to change its physical shape so that the impedance of the resonator may be adjusted. For example, the distance h between a conductor 731 of the matcher 730 and the ground conducting portion 713 may be increased or decreased based on the control signal.
- the controller may generate the control signal based on various factors.
- the matcher 730 may be configured as a passive element such as the conductor 731 , for example.
- the matcher 730 may be configured as an active element such as a diode, a transistor, or the like. If the active element is included in the matcher 730 , the active element may be driven based on the control signal generated by the controller, and the impedance of the resonator 700 may be adjusted based on the control signal. For example, when the active element is a diode included in the matcher 730 the impedance of the resonator 700 may be adjusted depending on whether the diode is in an ON state or in an OFF state.
- a magnetic core may be further provided to pass through the MNG resonator 700 .
- the magnetic core may perform a function of increasing a power transmission distance.
- FIG. 8 illustrates a resonator 800 having a three-dimensional (3D) structure.
- the resonator 800 having the 3D structure may include a transmission line and a capacitor 820 .
- the transmission line may include a first signal conducting portion 811 , a second signal conducting portion 812 , and a ground conducting portion 813 .
- the capacitor 820 may be inserted, for instance, in series between the first signal conducting portion 811 and the second signal conducting portion 812 of the transmission link such that an electric field may be confined within the capacitor 820 .
- the resonator 800 may have a generally 3D structure.
- the transmission line may include the first signal conducting portion 811 and the second signal conducting portion 812 in an upper portion of the resonator 800 , and may include the ground conducting portion 813 in a lower portion of the resonator 800 .
- the first signal conducting portion 811 and the second signal conducting portion 812 may be disposed to face the ground conducting portion 813 .
- current may flow in an x direction through the first signal conducting portion 811 and the second signal conducting portion 812 . Due to the current, a magnetic field H(W) may be formed in a ⁇ y direction. However, it will be appreciated that, the magnetic field H(W) might also be formed in the opposite direction (e.g., a +y direction) in other implementations.
- one end of the first signal conducting portion 811 may be electrically connected (i.e., shorted) to a conductor 842 , and another end of the first signal conducting portion 811 may be connected to the capacitor 820 .
- One end of the second signal conducting portion 812 may be grounded to the conductor 841 , and another end of the second signal conducting portion 812 may be connected to the capacitor 820 .
- the first signal conducting portion 811 , the second signal conducting portion 812 , the ground conducting portion 813 , and the conductors 841 and 842 may be connected to each other, whereby the resonator 800 may have an electrically closed-loop structure. As shown in FIG.
- the capacitor 820 may be inserted or otherwise positioned between the first signal conducting portion 811 and the second signal conducting portion 812 .
- the capacitor 820 may be inserted into a space between the first signal conducting portion 811 and the second signal conducting portion 812 .
- the capacitor 820 may include, for example, a lumped element, a distributed element, or the like.
- a distributed capacitor having the shape of the distributed element may include zigzagged conductor lines and a dielectric material having a relatively high permittivity positioned between the zigzagged conductor lines.
- the resonator 800 may have a property of a metamaterial, in some instances, as discussed above.
- the resonator 800 may have the characteristic of the metamaterial.
- the resonator 800 may also be referred to as an MNG resonator.
- Various criteria may be applied to determine the capacitance of the capacitor 820 .
- the various criteria may include, for instance, one or more of the following: a criterion for enabling the resonator 800 to have the characteristic of the metamaterial, a criterion for enabling the resonator 800 to have a negative magnetic permeability in a target frequency, a criterion enabling the resonator 800 to have a zeroth order resonance characteristic in the target frequency, or the like. Based on at least one criterion among the aforementioned criteria, the capacitance of the capacitor 820 may be determined.
- the resonator 800 also referred to as the MNG resonator 800 , may have a zeroth order resonance characteristic (i.e., having, as a resonance frequency, a frequency when a propagation constant is “0”). If the resonator 800 has a zeroth order resonance characteristic, the resonance frequency may be independent with respect to a physical size of the MNG resonator 800 . Thus, by appropriately designing the capacitor 820 , the MNG resonator 800 may sufficiently change the resonance frequency without substantially changing the physical size of the MNG resonator 800 .
- the electric field may be concentrated on the capacitor 820 inserted into the transmission line. Accordingly, due to the capacitor 820 , the magnetic field may become dominant in the near field. And, since the MNG resonator 800 having the zeroth-order resonance characteristic may have characteristics similar to a magnetic dipole, the magnetic field may become dominant in the near field. A relatively small amount of the electric field formed due to the insertion of the capacitor 820 may be concentrated on the capacitor 820 and thus, the magnetic field may become further dominant.
- the MNG resonator 800 may include a matcher 830 for impedance-matching.
- the matcher 830 may be configured to appropriately adjust the strength of magnetic field of the MNG resonator 800 .
- the impedance of the MNG resonator 800 may be determined by the matcher 830 .
- current may flow in the MNG resonator 800 via a connector 840 , or may flow out from the MNG resonator 800 via the connector 840 .
- the connector 840 may be connected to the ground conducting portion 813 or the matcher 830 .
- the matcher 830 may be positioned within the loop formed by the loop structure of the resonator 800 .
- the matcher 830 may be configured to adjust the impedance of the resonator 800 by changing the physical shape of the matcher 830 .
- the matcher 830 may include the conductor 831 for the impedance-matching in a location separate from the ground conducting portion 813 by a distance h.
- the impedance of the resonator 800 may be changed by adjusting the distance h.
- a controller may be provided to control the matcher 830 .
- the matcher 830 may change the physical shape of the matcher 830 based on a control signal generated by the controller. For example, the distance h between the conductor 831 of the matcher 830 and the ground conducting portion 813 may be increased or decreased based on the control signal. Accordingly, the physical shape of the matcher 830 may be changed such that the impedance of the resonator 800 may be adjusted. The distance h between the conductor 831 of the matcher 830 and the ground conducting portion 813 may be adjusted using a variety of schemes.
- a plurality of conductors may be included in the matcher 830 and the distance h may be adjusted by adaptively activating one of the conductors.
- the distance h may be adjusted by adjusting the physical location of the conductor 831 up and down.
- the distance h may be controlled based on the control signal of the controller.
- the controller may generate the control signal using various factors.
- the matcher 830 may be configured as a passive element such as the conductor 831 , for instance.
- the matcher 830 may be configured as an active element such as, for example, a diode, a transistor, or the like.
- the active element When the active element is included in the matcher 830 , the active element may be driven based on the control signal generated by the controller, and the impedance of the resonator 800 may be adjusted based on the control signal. For example, if the active element is a diode included in the matcher 830 , the impedance of the resonator 800 may be adjusted depending on whether the diode is in an ON state or in an OFF state.
- a magnetic core may be further provided to pass through the resonator 800 configured as the MNG resonator.
- the magnetic core may perform a function of increasing a power transmission distance.
- FIG. 9 illustrates a resonator 900 for a wireless power transmission configured as a bulky type.
- the term “bulky type” may refer to a seamless connection connecting at least two parts in an integrated form.
- a first signal conducting portion 911 and a conductor 942 may be integrally formed instead of being separately manufactured and thereby be connected to each other.
- the second signal conducting portion 912 and a conductor 941 may also be integrally manufactured.
- the second signal conducting portion 912 and the conductor 941 When the second signal conducting portion 912 and the conductor 941 are separately manufactured and then are connected to each other, a loss of conduction may occur due to a seam 950 .
- the second signal conducting portion 912 and the conductor 941 may be connected to each other without using a separate seam, (i.e., seamlessly connected to each other). Accordingly, it is possible to decrease a conductor loss caused by the seam 950 .
- the second signal conducting portion 912 and a ground conducting portion 913 may be seamlessly and integrally manufactured.
- the first signal conducting portion 911 , the conductor 942 and the ground conducting portion 913 may be seamlessly and integrally manufactured.
- FIG. 10 illustrates a resonator 1000 for a wireless power transmission, configured as a hollow type.
- each of a first signal conducting portion 1011 , a second signal conducting portion 1012 , a ground conducting portion 1013 , and conductors 1041 and 1042 of the resonator 1000 configured as the hollow type structure.
- the term “hollow type” refers to a configuration that may include an empty space inside.
- an active current may be modeled to flow in only a portion of the first signal conducting portion 1011 instead of all of the first signal conducting portion 1011 , the second signal conducting portion 1012 instead of all of the second signal conducting portion 1012 , the ground conducting portion 1013 instead of all of the ground conducting portion 1013 , and the conductors 1041 and 1042 instead of all of the conductors 1041 and 1042 .
- a depth of each of the first signal conducting portion 1011 , the second signal conducting portion 1012 , the ground conducting portion 1013 , and the conductors 1041 and 1042 is significantly deeper than a corresponding skin depth in the given resonance frequency, it may be ineffective. The significantly deeper depth may, however, increase a weight or manufacturing costs of the resonator 1000 in some instances.
- the depth of each of the first signal conducting portion 1011 , the second signal conducting portion 1012 , the ground conducting portion 1013 , and the conductors 1041 and 1042 may be appropriately determined based on the corresponding skin depth of each of the first signal conducting portion 1011 , the second signal conducting portion 1012 , the ground conducting portion 1013 , and the conductors 1041 and 1042 .
- the resonator 1000 may become light, and manufacturing costs of the resonator 1000 may also decrease.
- the depth of the second signal conducting portion 1012 (as further illustrated in the enlarged view region 1060 indicated by a circle) may be determined as “d” mm and d may be determined according to
- f denotes a frequency
- ⁇ denotes a magnetic permeability
- ⁇ denotes a conductor constant.
- the skin depth may be about 0.6 mm with respect to 10 kHz of the resonance frequency and the skin depth may be about 0.006 mm with respect to 100 MHz of the resonance frequency.
- a capacitor 1020 and a matcher 1030 may be provided that are similarly constructed as described herein in one or more embodiments.
- FIG. 11 illustrates a resonator 1100 for a wireless power transmission using a parallel-sheet.
- the parallel-sheet may be applicable to each of a first signal conducting portion 1111 and a second signal conducting portion 1112 included in the resonator 1100 .
- Each of the first signal conducting portion 1111 and the second signal conducting portion 1112 may not be a perfect conductor and thus, may have an inherent resistance. Due to this resistance, an ohmic loss may occur. The ohmic loss may decrease a Q-factor and also decrease a coupling effect.
- each of the first signal conducting portion 1111 and the second signal conducting portion 1112 may include a plurality of conductor lines.
- the plurality of conductor lines may be disposed in parallel, and may be electrically connected (i.e., shorted) at an end portion of each of the first signal conducting portion 1111 and the second signal conducting portion 1112 .
- the plurality of conductor lines may be disposed in parallel. Accordingly, a sum of resistances having the conductor lines may decrease. Consequently, the resistance loss may decrease, and the Q-factor and the coupling effect may increase.
- FIG. 12 illustrates a resonator 1200 for a wireless power transmission, including a distributed capacitor.
- a capacitor 1220 included in the resonator 1200 is configured for the wireless power transmission.
- a capacitor used as a lumped element may have a relatively high equivalent series resistance (ESR).
- ESR equivalent series resistance
- a variety of schemes have been proposed to decrease the ESR contained in the capacitor of the lumped element.
- by using the capacitor 1220 as a distributed element it may be possible to decrease the ESR.
- a loss caused by the ESR may decrease a Q-factor and a coupling effect.
- the capacitor 1220 may be configured as a conductive line having the zigzagged structure.
- the capacitor 1220 By employing the capacitor 1220 as the distributed element, it may be possible to decrease the loss occurring due to the ESR in some instances.
- a plurality of capacitors As lumped elements, it is possible to decrease the loss occurring due to the ESR. Since a resistance of each of the capacitors as the lumped elements decreases through a parallel connection, active resistances of parallel-connected capacitors as the lumped elements may also decrease whereby the loss occurring due to the ESR may decrease. For example, by employing ten capacitors of 1 pF each instead of using a single capacitor of 10 pF, it may be possible to decrease the loss occurring due to the ESR in some instances.
- FIG. 13A illustrates one embodiment of the matcher 730 used in the resonator 700 provided in the 2D structure of FIG. 7
- FIG. 13B illustrates an example of the matcher 830 used in the resonator 800 provided in the 3D structure of FIG. 8 .
- FIG. 13A illustrates a portion of the 2D resonator including the matcher 730
- FIG. 13B illustrates a portion of the 3D resonator of FIG. 8 including the matcher 830 .
- the matcher 730 may include the conductor 731 , a conductor 732 , and a conductor 733 .
- the conductors 732 and 733 may be connected to the ground conducting portion 713 and the conductor 731 .
- the impedance of the 2D resonator may be determined based on a distance h between the conductor 731 and the ground conducting portion 713 .
- the distance h between the conductor 731 and the ground conducting portion 713 may be controlled by the controller.
- the distance h between the conductor 731 and the ground conducting portion 713 can be adjusted using a variety of schemes.
- the variety of schemes may include, for instance, one or more of the following: a scheme of adjusting the distance h by adaptively activating one of the conductors 731 , 732 , and 733 , a scheme of adjusting the physical location of the conductor 731 up and down, and/or the like.
- the matcher 830 may include the conductor 831 , a conductor 832 , a conductor 833 and conductors 841 and 842 .
- the conductors 832 and 833 may be connected to the ground conducting portion 813 and the conductor 831 .
- the conductors 841 and 842 may be connected to the ground conducting portion 813 .
- the impedance of the 3D resonator may be determined based on a distance h between the conductor 831 and the ground conducting portion 813 .
- the distance h between the conductor 831 and the ground conducting portion 813 may be controlled by the controller, for example.
- the distance h between the conductor 831 and the ground conducting portion 813 may be adjusted using a variety of schemes.
- the variety of schemes may include, for instance, one or more of the following: a scheme of adjusting the distance h by adaptively activating one of the conductors 831 , 832 , and 833 , a scheme of adjusting the physical location of the conductor 831 up and down, or the like.
- the matcher may include an active element.
- a scheme of adjusting an impedance of a resonator using the active element may be similar as described above.
- the impedance of the resonator may be adjusted by changing a path of a current flowing through the matcher using the active element.
- FIG. 14 illustrates one equivalent circuit of the resonator 700 for the wireless power transmission of FIG. 7 .
- the resonator 700 of FIG. 7 for the wireless power transmission may be modeled to the equivalent circuit of FIG. 14 .
- L R denotes an inductance of the power transmission line
- C L denotes the capacitor 720 that is inserted in a form of a lumped element in the middle of the power transmission line
- C R denotes a capacitance between the power transmissions and/or ground of FIG. 7 .
- the resonator 700 may have a zeroth resonance characteristic. For example, when a propagation constant is “0”, the resonator 700 may be assumed to have ⁇ MZR as a resonance frequency.
- the resonance frequency ⁇ MZR may be expressed by Equation 2.
- Equation 2 MZR denotes a Mu zero resonator.
- the resonance frequency ⁇ MZR of the resonator 700 may be determined by
- a physical size of the resonator 700 and the resonance frequency ⁇ MZR may be independent with respect to each other. Since the physical sizes are independent with respect to each other, the physical size of the resonator 700 may be sufficiently reduced.
- a DC/DC converter may detect an amount of current of a DC/DC converter without directly sensing the amount of current of the DC/DC converter, and may control a turn-on period of a turn-on switch based on detected amount of current. When the amount of current is low, the DC/DC converter may decrease the turn-on period to reduce a switching loss.
- Non-transitory computer-readable media including program instructions to implement various operations embodied by a computer.
- the media may also include, alone or in combination with the program instructions, data files, data structures, and the like.
- Examples of non-transitory computer-readable media include magnetic media such as hard disks, floppy disks, and magnetic tape; optical media such as CD ROM discs and DVDs; magneto-optical media such as optical discs; and hardware devices that are specially configured to store and perform program instructions, such as read-only memory (ROM), random access memory (RAM), flash memory, and the like.
- Examples of program instructions include both machine code, such as produced by a compiler, and files containing higher level code that may be executed by the computer using an interpreter.
- the described hardware devices may be configured to act as one or more software modules in order to perform the operations of the above-described example embodiments, or vice versa.
- a non-transitory computer-readable storage medium may be distributed among computer systems connected through a network and non-transitory computer-readable codes or program instructions may be stored and executed in a decentralized manner.
Abstract
Description
- This application claims the benefit under 35 U.S.C. §119(a) of Korean Patent Application No. 10-2010-0130861, filed on Dec. 20, 2010, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes.
- 1. Field
- The following description relates to a direct current-direct current (DC/DC) converter for use in a wireless power receiver.
- 2. Description of Related Art
- Direct current-direct current (DC/DC) converters are generally used in wireless power transmission systems, portable multimedia devices, and/or the like. They may be configured to receive a DC voltage and then may raise or reduce the voltage to a voltage of a stable level requested by an output unit. In one conventional DC/DC converter, an input unit may provide the output unit with a voltage that is requested by the output unit and thus, an efficiency of the DC/DC converter may approach 100%. The efficiency of DC/DC converter may be reduced for many reasons including a switching loss and a conduction loss.
- The switching loss may occur, for instance when a transistor that corresponds to a switch and that is included in the DC/DC converter is turned on, and the conduction loss may occur due to a parasitic resistance of the transistor and a parasitic resistance of an inductor inside the DC/DC converter. While the switching loss may be assumed to be a constant value (regardless of a magnitude of an inputted current), the conduction loss may be proportional to the inputted current. Thus, when a low current is inputted, a component of the switching loss may be higher than a component of the conduction loss, and efficiency may decrease.
- According to an aspect, a direct current-direct current (DC/DC) converter for use in a wireless power receiver may include: a voltage converting unit configured to convert, DC voltage, to a predetermined DC voltage; a turn-on switch configured to control current flow of the DC voltage through the voltage converting unit; and a switching controller configured to: detect an amount of current of the voltage converting unit based on a first turn-on period of the turn-on switch, set a second turn-on period of the turn-on switch based on the detected amount of current, and control the turn-on switch based on the second turn-on period.
- The amount of current of the voltage converting unit may comprise an amount of current inputted to the voltage converting unit or an amount of current outputted from the voltage converting unit.
- When the detected amount of current is greater than a predetermined reference value, the switching controller may be configured to set the second turn-on period to be shorter when the detected amount of current is less than or equal to the predetermined reference value.
- When the detected amount of current is less than a predetermined reference value, the switching controller may be configured to set the second turn-on period to be longer when the detected amount of current is greater than or equal to the predetermined reference.
- The switching controller may include: a voltage divider configured to divide, in a predetermined ratio, a voltage outputted from the voltage converting unit; an error amplifier configured to amplify and output a difference value between an output voltage of the voltage divider and a predetermined reference voltage; a first comparator configured to compare the output of the error amplifier with a ramp signal, to output a pulse width modulator (PWM) signal to be used for switching the turn-on switch; a controller configured to set the second turn-on period based on the PWM signal, and to control the turn-on switch based on the second turn-on period; a current detecting unit configured to detect the amount of current of the voltage converting unit based on the first turn-on period of the turn-on switch, and to generate a frequency control signal that controls a frequency of the ramp signal based on the detected amount of current; and a generator configured to control the frequency of the ramp signal based on the frequency control signal, and to output the ramp signal having a changed frequency to the first comparator.
- The current detecting unit may include: an electric charge pump configured to output electric charges during a turn-on time where the turn-on switch is turned on based on a turn-on period; a capacitor configured to be charged with electric charges outputted from the electric charge pump during the turn-on time based on the turn-on period, and to discharge electric charges during a turn-off time based on the turn-on period, to output a current measurement voltage; a second comparator configured to compare a current measurement reference voltage with the current measurement voltage; and a controller configured to output a frequency control signal that increases the frequency of the ramp signal when the comparison of the second comparator indicates that the current measurement voltage is greater than the current measurement reference voltage, and to output a frequency control signal that decreases the frequency of the ramp signal when the comparison of the second comparator indicates that the current measurement voltage is less than the current measurement reference voltage.
- The second comparator may include a hysteresis comparator that is configured to compare the current measurement voltage with a high-reference voltage or with a low-reference voltage; and the frequency controller may be configured to output a frequency control signal that increases the frequency of the ramp signal when the current measurement voltage is greater than the high-reference voltage, and to output a frequency control signal that decreases the frequency of the ramp signal when the current measurement voltage is less than the low-reference voltage.
- According to an aspect, a wireless power receiver may include: a target resonator configured to receive electromagnetic energy from a source resonator; a rectifier configured to rectify an alternating current (AC) signal received from the target resonator, to generate a direct current (DC) signal; and a DC/DC converter configured to adjust a signal level of the DC signal, to output a rated voltage, the DC/DC converter comprises: a voltage converting unit configured to convert, DC voltage, to a predetermined DC voltage; a turn-on switch configured to control current flow of the DC voltage through the voltage converting unit; and a switching controller configured to: detect an amount of current of the voltage converting unit based on a first turn-on period of the turn-on switch, set a second turn-on period of the turn-on switch based on the detected amount of current, and control the turn-on switch based on the second turn-on period.
- According to an aspect, a method for converting direct current to direct current (DC/DC) may include: converting, DC voltage, to a predetermined DC voltage; controlling current flow of the DC voltage via a turn-on switch; detecting an amount of current based on a first turn-on period on the turn-on switch; and setting a second turn-on period of the turn-on switch based on the detected amount of current.
- Other features and aspects may be apparent from the following detailed description, the drawings, and the claims.
-
FIG. 1 is a diagram illustrating a wireless power transmission system. -
FIG. 2 is a diagram illustrating a direct current-direct current (DC/DC) converter that reduces a switching loss. -
FIG. 3 is a diagram illustrating a current detecting unit in a DC/DC converter. -
FIG. 4 is a diagram illustrating a main timing of a DC/DC converter. -
FIG. 5 is a diagram illustrating a case where a current measurement voltage VC is less than low-reference voltage in a current detecting unit of a DC/DC converter. -
FIG. 6 is a diagram illustrating a case where a current measurement voltage VC is greater than a high-reference voltage in a current detecting unit of a DC/DC converter. -
FIGS. 7 through 13 are diagrams illustrating a resonator structure. -
FIG. 14 is a diagram illustrating one equivalent circuit of a resonator for wireless power transmission ofFIG. 7 . - Throughout the drawings and the detailed description, unless otherwise described, the same drawing reference numerals should be understood to refer to the same elements, features, and structures. The relative size and depiction of these elements may be exaggerated for clarity, illustration, and convenience.
- The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses and/or systems described herein. Accordingly, various changes, modifications, and equivalents of the systems, apparatuses and/or methods described herein may be suggested to those of ordinary skill in the art. The progression of processing steps and/or operations described is an example; however, the sequence of and/or operations is not limited to that set forth herein and may be changed as is known in the art, with the exception of steps and/or operations necessarily occurring in a certain order. Also, descriptions of well-known functions and constructions may be omitted for increased clarity and conciseness.
-
FIG. 1 illustrates a wireless power transmission system. In one or more embodiments, wireless power transmitted may be resonance power. - As shown in
FIG. 1 , the wireless power transmission system may have a source-target structure including a source and a target. For example, the wireless power transmission system may include aresonance power transmitter 110 corresponding to the source and aresonance power receiver 120 corresponding to the target. - The
resonance power transmitter 110 may include asource unit 111 and asource resonator 115. Thesource unit 111 may be configured to receive energy from an external voltage supplier to generate a resonance power. In some instances, theresonance power transmitter 110 may further include a matchingcontrol 113 to perform resonance frequency or impedance matching. - The
source unit 111 may include an alternating current (AC)-to-AC (AC/AC) converter, an AC-to-direct current (DC) (AC/DC) converter, and/or a (DC/AC) inverter. The AC/AC converter may be configured to adjust, to a desired level, a signal level of an AC signal input from an external device. And the AC/DC converter may output a DC voltage at a predetermined level by rectifying an AC signal output from the AC/AC converter. The DC/AC inverter may be configured to generate an AC signal (e.g., in a band of a few megahertz (MHz) to tens of MHz) by quickly switching a DC voltage output from the AC/DC converter. Of course, other frequencies of AC power are also possible. - The
matching control 113 may be configured to set at least a resonance bandwidth of thesource resonator 115, an impedance matching frequency of thesource resonator 115, or both. In some implementations, thematching control 113 may include at least one of a source resonance bandwidth setting unit and a source matching frequency setting unit. And the source resonance bandwidth setting unit may set the resonance bandwidth of thesource resonator 115. The source matching frequency setting unit may set the impedance matching frequency of thesource resonator 115. For example, a Q-factor of thesource resonator 115 may be determined based on setting of the resonance bandwidth of thesource resonator 115 or setting of the impedance matching frequency of thesource resonator 115. - The
source resonator 115 may be configured to transfer electromagnetic energy to atarget resonator 121. For example, thesource resonator 115 may transfer the resonance power to theresonance power receiver 120 throughmagnetic coupling 101 with thetarget resonator 121. Accordingly, thesource resonator 115 may be configured to resonate within the set resonance bandwidth. - As shown, the
resonance power receiver 120 may include thetarget resonator 121, amatching control 123 to perform resonance frequency or impedance matching, and atarget unit 125 to transfer the received resonance power to a device or a load. - The
target resonator 121 may be configured to receive the electromagnetic energy from thesource resonator 115. Thetarget resonator 121 may be configured to resonate within the set resonance bandwidth. - The matching
control 123 may set at least one of a resonance bandwidth of thetarget resonator 121 and an impedance matching frequency of thetarget resonator 121. In some implementations, the matchingcontrol 123 may include at least one of a target resonance bandwidth setting unit and a target matching frequency setting unit. The target resonance bandwidth setting unit may set the resonance bandwidth of thetarget resonator 121. The target matching frequency setting unit may be configured to set the impedance matching frequency of thetarget resonator 121. For example, a Q-factor of thetarget resonator 121 may be determined based on setting of the resonance bandwidth of thetarget resonator 121 or setting of the impedance matching frequency of thetarget resonator 121. - The
target unit 125 may be configured to transfer the received resonance power to the load. Thetarget unit 125 may include an AC/DC converter and a DC/DC converter. The AC/DC converter may generate a DC voltage by rectifying an AC signal transmitted from thesource resonator 115 to thetarget resonator 121. And the DC/DC converter may supply a rated voltage to a device or the load by adjusting a voltage level of the DC voltage. For example, the AC/DC converter may be configured as an active rectifier utilizing a delay locked loop. - In one or more embodiments, the
source resonator 115 and thetarget resonator 121 may be configured in a helix coil structured resonator, a spiral coil structured resonator, a meta-structured resonator, or the like. - Referring to
FIG. 1 , controlling the Q-factor may include setting the resonance bandwidth of thesource resonator 115 and the resonance bandwidth of thetarget resonator 121, and transferring the electromagnetic energy from thesource resonator 115 to thetarget resonator 121 throughmagnetic coupling 101 between thesource resonator 115 and thetarget resonator 121. The resonance bandwidth of thesource resonator 115 may be set to be wider or narrower than the resonance bandwidth of thetarget resonator 121 in some instances. For example, an unbalanced relationship between a BW-factor of thesource resonator 115 and a BW-factor of thetarget resonator 121 may be maintained by setting the resonance bandwidth of thesource resonator 115 to be wider or narrower than the resonance bandwidth of thetarget resonator 121. - For a wireless power transmission employing a resonance scheme, the resonance bandwidth may be an important factor. When the Q-factor (e.g., considering all of a change in a distance between the
source resonator 115 and thetarget resonator 121, a change in the resonance impedance, impedance mismatching, a reflected signal, and/or the like) is Qt, Qt may have an inverse-proportional relationship with the resonance bandwidth, as given byEquation 1. -
- In
Equation 1, f0 denotes a central frequency, Δf denotes a change in a bandwidth, ΓS,D denotes a reflection loss between thesource resonator 115 and thetarget resonator 121, BWS denotes the resonance bandwidth of thesource resonator 115, and BWD denotes the resonance bandwidth of thetarget resonator 121. InEquation 1, the BW-factor may indicate either 1/BWS or 1/BWD. - Due to an external effect, for example, a change in the distance between the
source resonator 115 and thetarget resonator 121, a change in a location of at least one of thesource resonator 115 and thetarget resonator 121, and/or the like, impedance mismatching between thesource resonator 115 and thetarget resonator 121 may occur. The impedance mismatching may be a direct cause in decreasing an efficiency of power transfer. When a reflected wave corresponding to a transmission signal that is partially reflected and returned is detected, the matchingcontrol 113 may be configured to determine the impedance mismatching has occurred, and may perform impedance matching. The matchingcontrol 113 may change a resonance frequency by detecting a resonance point through a waveform analysis of the reflected wave. The matchingcontrol 113 may determine, as the resonance frequency, a frequency having a minimum amplitude in the waveform of the reflected wave. - The
source resonator 115 and/or thetarget resonator 121 inFIG. 1 may have a resonator structure illustrated inFIGS. 7 through 14 . -
FIG. 2 illustrates a DC/DC converter 200 that reduces a switching loss. - As shown, the DC/
DC converter 200 may include avoltage converting unit 220 that converts a voltage of a DC signal VIN received from avoltage source 210 to a predetermined DC voltage VOUT. The predetermined DC voltage VOUT may be provided to aload 230. The DC/DC converter 200 may also include a switchingcontroller 240 that controls thevoltage converting unit 220. This may include turning on and off thevoltage converting unit 220 is some embodiments. - The
voltage converting unit 220 may be configured to convert the voltage of the DC signal provided when a current flows through a turn-onswitch 222, to the predetermined DC voltage VOUT. Thevoltage converting unit 220 may include the turn-onswitch 222, asecond switch 224, aninductor 226, and acapacitor 228. - For example, in one embodiment, the turn-on
switch 222 may be a switch configured to be turned on based on a switching signal VP of the switchingcontroller 240 so as to enable the DC current received from thevoltage source 210 to flow through the turn-onswitch 222, to provide the DC current IL to theinductor 226. - The
second switch 224 may be a switch that operates in reverse to the turn-onswitch 222, and may be turned on when the turn-onswitch 222 is turned off, based on a switching signal VN of the switchingcontroller 240. When thesecond switch 224 is turned on, the second switch may be grounded to an input of theinductor 226, for instance. - When the turn-on
switch 222 is turned on, theinductor 226 and thecapacitor 228 may receive the DC current via the turn-onswitch 222, may be charged with the received DC current, and may output a DC of the predetermined voltage VOUT. - In one or more embodiments, the turn-on switch 22 may include a p-channel metal-oxide semiconductor (PMOS) transistor MP, and, the
second switch 224 may include a similar transistor MN. Of course, it will be appreciated that other switches or switch elements may be used for the turn-off 222 switch and/or thesecond switch 224. For example, the switches or switch elements of the switching device may include various electromechanical switches (e.g., contact, toggle, knife, tilt, or the like) or electrical switches (e.g., solenoid, relays, or solid-state elements such as a transistor switch, silicon-controlled rectifier or a triac). Of course, other types of switches are also possible. In various embodiments, the switch may be configured to activate. For example, the switches may select between ON and OFF positions, which permit and prevent the flow of electricity (power), respectively. Accordingly, the switches control may control electrical connection. - The switching
controller 240 may detect an amount of current of thevoltage converting unit 220 based on a first turn-on period indicating a turn-on period of the turn-onswitch 222 at a current point in time. The switchingcontroller 240 may set a second turn-on period indicating a turn-on period that is to be applied to the turn-onswitch 222 based on the detected amount of current, and may control the turn-onswitch 222 based on the second turn-on period. For example, the amount of current of thevoltage converting unit 220 may be an amount of current inputted to thevoltage converting unit 220 or an amount of current outputted from thevoltage converting unit 220. - When the amount of current of the
voltage converting unit 220 is greater than a predetermined reference value, the switchingcontroller 240 may be configured to set the second turn-on period to be shorter when the amount of current of thevoltage converting unit 220 is less than or equal to the predetermined reference value. - When the amount of current of the
voltage converting unit 220 is less than a predetermined reference value, the switchingcontroller 240 may set the second turn-on period to be longer when the amount of current of thevoltage converting unit 220 is greater than or equal to the predetermined reference value. - The switching
controller 240 may include avoltage divider 243, areference voltage source 244, anerror amplifier 245, acapacitor 246, acomparator 247, acontroller 248, agenerator 249, and a current detectingunit 250. - The
voltage divider 243 may be configured to divide a voltage outputted from thevoltage converting unit 220. For example, the voltage may be divided in a predetermined ratio using two resistors 241 (R1) and 242 (R2), and may output the divided voltage to theerror amplifier 245. - The error amplifier (EA) 245 may be configured to amplify and output a difference value between the output voltage of the
voltage divider 243 and a predetermined reference voltage VREF outputted from thereference voltage source 244. - The
capacitor 246 may be charged with the output voltage of theerror amplifier 245, and may remove noise. - The comparator (COMP) 247 may compare the output of the
error amplifier 245 that passes through thecapacitor 246 with a ramp signal VRAMP outputted from thegenerator 249, and may output a pulse width modulator (PWM) signal to be used for switching the turn-onswitch 222. - The
controller 248 may be configured to set the second turn-on period to be applied to the turn-onswitch 222, based on the PWM signal outputted from thecomparator 247, and may control the turn-onswitch 222 based on the second turn-on period. - The current detecting
unit 250 may be configured to detect an amount of current of thevoltage converting unit 220 based on the first turn-on period of the turn-onswitch 222, and may generate a frequency control signal that can be used to control a frequency of the ramp signal VRAMP based on the detected amount of current of thevoltage converting unit 220. - The
generator 249 may be configured to control the frequency of the ramp signal VRAMP based on the frequency control signal received from the current detectingunit 250, and may output the ramp signal VRAMP having the changed frequency to thecomparator 247. In addition, thegenerator 249 may be configured to output a clock timing signal ΦCLK to thecontroller 248 based on the frequency control signal received from the current detectingunit 250. -
FIG. 3 illustrates a current detecting unit in a DC/DC converter. Referring toFIG. 3 , one embodiment of the current detectingunit 250 ofFIG. 2 may include anelectric charge pump 310, acapacitor 320, acomparator 330, and afrequency controller 340. - The
electric charge pump 310 may be configured to output electric charges during a turn-on time tON where the turn-onswitch 222 is turned on based on a turn-on period T. For example, theelectric charge pump 310 may be configured to include acurrent source 312, afirst switch 314, and asecond switch 316. - The
current source 312 may output a predetermined amount of electric charge. For example, thefirst switch 314 may output electric charges during the turn-on time tON where the turn-onswitch 222 is turned on based on the turn-on period. And thesecond switch 316 may be grounded and may operate in reverse to thefirst switch 314. - The
capacitor 320 may be charged with the electric charges outputted from theelectric charge pump 310 based on the turn-on period of the turn-onswitch 222, and may discharge electric charges during a turn-off time based on the turn-on period, to output a current measurement voltage to be used for measuring an amount of current. - The
comparator 330 may be configured to compare a current measurement reference voltage (e.g., VREF— H or VREF— L as discussed below) with the current measurement voltage outputted from thecapacitor 320, and may transmit a result of the comparison to thefrequency controller 340. - The
frequency controller 340 may be configured to output a frequency control signal that increases a frequency of a ramp signal when the current measurement voltage is greater than a current measurement reference voltage, and may output a frequency control signal that decreases the frequency of the ramp signal when the current measurement voltage is less than the current measurement reference voltage. - For example, the
frequency controller 340 may output the frequency control signal by classifying the frequency of the ramp signal as a reference frequency, ½ reference frequency, ¼ reference frequency, and ⅛ reference frequency. - Even though the frequency of the ramp signal may be changed to be higher, the period of the PWM signal outputted from the
comparator 247 ofFIG. 1 may become shorter and the period of the turn-on signal outputted from thecontroller 248 may become shorter. Thus, the turn-onswitch 222 may be more frequently turned on and turned off. - For example, when the frequency of the ramp signal may be changed to be lower, the period of the PWM signal outputted from the
comparator 247 ofFIG. 1 may become long and the period of the turn-on signal outputted from thecontroller 248 may become longer. Accordingly, in this case, the turn-onswitch 222 may be less frequently turned on and turned off. -
FIG. 4 illustrates a main timing of a DC/DC converter. In particular,FIG. 4 shows waveforms for the clock timing signal ΦCLK the switching signal VP input to the turn-onswitch 222, the switching signal VN input to thesecond switch 224, the current IL of theinductor 226, and a current measurement voltage VC that is outputted from thecapacitor 320 of the current detectingunit 250 over corresponding times periods. - As will be appreciated, the current measurement voltage VC may be similar to a waveform of a current IL outputted from the
inductor 226. - Accordingly, the current detecting
unit 250 may be configured to estimate a magnitude of a peak of the current IL of theinductor 226 without (directly) sensing the current IL of theinductor 226, for instance. - In one or more embodiment, as the amount of current of the
voltage converting unit 220 decreases, a turn-on time of the turn-onswitch 222 decreases and thus, the peak of the current IL of theinductor 226 and a peak of the current measurement voltage VC may decrease. - The
comparator 330 may be configured to compare the current measurement voltage VC with two reference voltages: a high-reference voltage (VREF_H) or a low-reference voltage (VREF_L). For example, thecomparator 330 may be a hysteresis comparator. - When the current measurement voltage VC is less than VREF_L, the
frequency controller 340 may determine that the amount of current is insufficient for a current frequency.FIG. 5 illustrates when a current measurement voltage VC is less than VREF_L in a current detecting unit of a DC/DC converter. - When the current measurement voltage VC is less than VREF_L, the
frequency controller 340 may output a frequency control signal that decreases a frequency of a ramp signal. - On the other hand, when the current measurement voltage VC is greater than VREF_H, the
frequency controller 340 may determine that the amount of current is excessive for a current frequency. -
FIG. 6 illustrates a case where a current measurement voltage VC is greater than VREF_H in a current detecting unit of a DC/DC converter. When the current measurement voltage VC is greater than the VREF_H, thefrequency controller 340 may output a frequency control signal that increases a frequency of a ramp signal. - Referring again to
FIG. 1 , the source resonator and/or the target resonator of the wireless power transmission system may be configured as a helix coil structured resonator, a spiral coil structured resonator, a meta-structured resonator, or the like. - One or more of the materials of the embodiment disclosed herein may be metamaterials.
- An electromagnetic characteristic of many materials found in nature is that they have a unique magnetic permeability or a unique permittivity. Most materials typically have a positive magnetic permeability or a positive permittivity. Thus, for these materials, a right hand rule may be applied to an electric field, a magnetic field, and a pointing vector and thus, the corresponding materials may be referred to as right handed materials (RHMs).
- On the other hand, a material having a magnetic permeability or a permittivity which is not ordinarily found in nature or is artificially-designed (or man-made) may be referred to herein as a “metamaterial.” Metamaterials may be classified into an epsilon negative (ENG) material, a mu negative (MNG) material, a double negative (DNG) material, a negative refractive index (NRI) material, a left-handed (LH) material, and the like, based on a sign of the corresponding permittivity or magnetic permeability.
- The magnetic permeability may indicate a ratio between a magnetic flux density occurring with respect to a given magnetic field in a corresponding material and a magnetic flux density occurring with respect to the given magnetic field in a vacuum state. The permittivity indicates a ratio between an electric flux density, occurring with respect to a given electric field in a corresponding material, and an electric flux density, occurring with respect to the given electric field, in a vacuum state. The magnetic permeability and the permittivity, in some embodiments, may be used to determine a propagation constant of a corresponding material in a given frequency or a given wavelength. An electromagnetic characteristic of the corresponding material may be determined based on the magnetic permeability and the permittivity. According to an aspect, the metamaterial may be easily disposed in a resonance state without significant material size changes. This may be practical for a relatively large wavelength area or a relatively low frequency area, for instance.
-
FIG. 7 illustrates aresonator 700 having a two-dimensional (2D) structure. - As shown, the
resonator 700 having the 2D structure may include a transmission line, acapacitor 720, amatcher 730, andconductors signal conducting portion 711, a secondsignal conducting portion 712, and aground conducting portion 713. - The
capacitor 720 may be inserted or otherwise positioned in series between the firstsignal conducting portion 711 and the secondsignal conducting portion 712 so that an electric field may be confined within thecapacitor 720. In various implementations, the transmission line may include at least one conductor in an upper portion of the transmission line, and may also include at least one conductor in a lower portion of the transmission line. A current may flow through the at least one conductor disposed in the upper portion of the transmission line and the at least one conductor disposed in the lower portion of the transmission may be electrically grounded. As shown inFIG. 7 , theresonator 700 may be configured to have a generally 2D structure. The transmission line may include the firstsignal conducting portion 711 and the secondsignal conducting portion 712 in the upper portion of the transmission line, and may include theground conducting portion 713 in the lower portion of the transmission line. As shown, the firstsignal conducting portion 711 and the secondsignal conducting portion 712 may be disposed to face theground conducting portion 713 with current flowing through the firstsignal conducting portion 711 and the secondsignal conducting portion 712. - In some implementations, one end of the first
signal conducting portion 711 may be electrically connected (i.e., shorted) to aconductor 742, and another end of the firstsignal conducting portion 711 may be connected to thecapacitor 720. And one end of the secondsignal conducting portion 712 may be grounded to theconductor 741, and another end of the secondsignal conducting portion 712 may be connected to thecapacitor 720. Accordingly, the firstsignal conducting portion 711, the secondsignal conducting portion 712, theground conducting portion 713, and theconductors resonator 700 may have an electrically “closed-loop structure.” The term “closed-loop structure” as used herein, may include a polygonal structure, for example, a circular structure, a rectangular structure, or the like that is electrically closed. Thecapacitor 720 may be inserted into an intermediate portion of the transmission line. For example, thecapacitor 720 may be inserted into a space between the firstsignal conducting portion 711 and the secondsignal conducting portion 712. Thecapacitor 720 may be configured, in some instances, as a lumped element, a distributed element, or the like. In one implementation, a distributed capacitor may be configured as a distributed element and may include zigzagged conductor lines and a dielectric material having a relatively high permittivity between the zigzagged conductor lines. - When the
capacitor 720 is inserted into the transmission line, theresonator 700 may have a property of a metamaterial, as discussed above. For example, theresonator 700 may have a negative magnetic permeability due to the capacitance of thecapacitor 720. If so, theresonator 700 may be referred to as a mu negative (MNG) resonator. Various criteria may be applied to determine the capacitance of thecapacitor 720. For example, the various criteria for enabling theresonator 700 to have the characteristic of the metamaterial may include one or more of the following: a criterion for enabling theresonator 700 to have a negative magnetic permeability in a target frequency, a criterion for enabling theresonator 700 to have a zeroth order resonance characteristic in the target frequency, or the like. - The
resonator 700, also referred to as theMNG resonator 700, may also have a zeroth order resonance characteristic (i.e., having, as a resonance frequency, a frequency when a propagation constant is “0”). If theresonator 700 has the zeroth order resonance characteristic, the resonance frequency may be independent with respect to a physical size of theMNG resonator 700. Moreover, by appropriately designing thecapacitor 720, theMNG resonator 700 may sufficiently change the resonance frequency without substantially changing the physical size of theMNG resonator 700 may not be changed. - In a near field, for instance, the electric field may be concentrated on the
capacitor 720 inserted into the transmission line. Accordingly, due to thecapacitor 720, the magnetic field may become dominant in the near field. In one or more embodiments, theMNG resonator 700 may have a relatively high Q-factor using thecapacitor 720 of the lumped element. Thus, it may be possible to enhance power transmission efficiency. For example, the Q-factor indicates a level of an ohmic loss or a ratio of a reactance with respect to a resistance in the wireless power transmission. The efficiency of the wireless power transmission may increase according to an increase in the Q-factor. - The
MNG resonator 700 may include amatcher 730 for impedance-matching. For example, thematcher 730 may be configured to appropriately determine and adjust the strength of a magnetic field of theMNG resonator 700, for instance. Depending on the configuration, current may flow in theMNG resonator 700 via a connector, or may flow out from theMNG resonator 700 via the connector. The connector may be connected to theground conducting portion 713 or thematcher 730. In some instances, power may be transferred through coupling without using a physical connection between the connector and theground conducting portion 713 or thematcher 730. - As shown in
FIG. 7 , thematcher 730 may be positioned within the loop formed by the loop structure of theresonator 700. Thematcher 730 may adjust the impedance of theresonator 700 by changing the physical shape of thematcher 730. For example, thematcher 730 may include theconductor 731 for the impedance-matching positioned in a location that is separate from theground conducting portion 713 by a distance h. Accordingly, the impedance of theresonator 700 may be changed by adjusting the distance h. In some instances, a controller may be provided to control thematcher 730 which generates and transmits a control signal to thematcher 730 directing the matcher to change its physical shape so that the impedance of the resonator may be adjusted. For example, the distance h between aconductor 731 of thematcher 730 and theground conducting portion 713 may be increased or decreased based on the control signal. The controller may generate the control signal based on various factors. - As shown in
FIG. 7 , thematcher 730 may be configured as a passive element such as theconductor 731, for example. Of course, in other embodiments, thematcher 730 may be configured as an active element such as a diode, a transistor, or the like. If the active element is included in thematcher 730, the active element may be driven based on the control signal generated by the controller, and the impedance of theresonator 700 may be adjusted based on the control signal. For example, when the active element is a diode included in thematcher 730 the impedance of theresonator 700 may be adjusted depending on whether the diode is in an ON state or in an OFF state. - In some instances, a magnetic core may be further provided to pass through the
MNG resonator 700. The magnetic core may perform a function of increasing a power transmission distance. -
FIG. 8 illustrates aresonator 800 having a three-dimensional (3D) structure. - Referring to
FIG. 8 , theresonator 800 having the 3D structure may include a transmission line and acapacitor 820. The transmission line may include a first signal conducting portion 811, a second signal conducting portion 812, and aground conducting portion 813. Thecapacitor 820 may be inserted, for instance, in series between the first signal conducting portion 811 and the second signal conducting portion 812 of the transmission link such that an electric field may be confined within thecapacitor 820. - As shown in
FIG. 8 , theresonator 800 may have a generally 3D structure. The transmission line may include the first signal conducting portion 811 and the second signal conducting portion 812 in an upper portion of theresonator 800, and may include theground conducting portion 813 in a lower portion of theresonator 800. The first signal conducting portion 811 and the second signal conducting portion 812 may be disposed to face theground conducting portion 813. In this arrangement, current may flow in an x direction through the first signal conducting portion 811 and the second signal conducting portion 812. Due to the current, a magnetic field H(W) may be formed in a −y direction. However, it will be appreciated that, the magnetic field H(W) might also be formed in the opposite direction (e.g., a +y direction) in other implementations. - In one or more embodiments, one end of the first signal conducting portion 811 may be electrically connected (i.e., shorted) to a
conductor 842, and another end of the first signal conducting portion 811 may be connected to thecapacitor 820. One end of the second signal conducting portion 812 may be grounded to theconductor 841, and another end of the second signal conducting portion 812 may be connected to thecapacitor 820. Accordingly, the first signal conducting portion 811, the second signal conducting portion 812, theground conducting portion 813, and theconductors resonator 800 may have an electrically closed-loop structure. As shown inFIG. 8 , thecapacitor 820 may be inserted or otherwise positioned between the first signal conducting portion 811 and the second signal conducting portion 812. For example, thecapacitor 820 may be inserted into a space between the first signal conducting portion 811 and the second signal conducting portion 812. Thecapacitor 820 may include, for example, a lumped element, a distributed element, or the like. In one implementation, a distributed capacitor having the shape of the distributed element may include zigzagged conductor lines and a dielectric material having a relatively high permittivity positioned between the zigzagged conductor lines. - When the
capacitor 820 is inserted into the transmission line, theresonator 800 may have a property of a metamaterial, in some instances, as discussed above. - For example, when a capacitance of the capacitor inserted is a lumped element, the
resonator 800 may have the characteristic of the metamaterial. When theresonator 800 has a negative magnetic permeability by appropriately adjusting the capacitance of thecapacitor 820, theresonator 800 may also be referred to as an MNG resonator. Various criteria may be applied to determine the capacitance of thecapacitor 820. For example, the various criteria may include, for instance, one or more of the following: a criterion for enabling theresonator 800 to have the characteristic of the metamaterial, a criterion for enabling theresonator 800 to have a negative magnetic permeability in a target frequency, a criterion enabling theresonator 800 to have a zeroth order resonance characteristic in the target frequency, or the like. Based on at least one criterion among the aforementioned criteria, the capacitance of thecapacitor 820 may be determined. - The
resonator 800, also referred to as theMNG resonator 800, may have a zeroth order resonance characteristic (i.e., having, as a resonance frequency, a frequency when a propagation constant is “0”). If theresonator 800 has a zeroth order resonance characteristic, the resonance frequency may be independent with respect to a physical size of theMNG resonator 800. Thus, by appropriately designing thecapacitor 820, theMNG resonator 800 may sufficiently change the resonance frequency without substantially changing the physical size of theMNG resonator 800. - Referring to the
MNG resonator 800 ofFIG. 8 , in a near field, the electric field may be concentrated on thecapacitor 820 inserted into the transmission line. Accordingly, due to thecapacitor 820, the magnetic field may become dominant in the near field. And, since theMNG resonator 800 having the zeroth-order resonance characteristic may have characteristics similar to a magnetic dipole, the magnetic field may become dominant in the near field. A relatively small amount of the electric field formed due to the insertion of thecapacitor 820 may be concentrated on thecapacitor 820 and thus, the magnetic field may become further dominant. - Also, the
MNG resonator 800 may include amatcher 830 for impedance-matching. Thematcher 830 may be configured to appropriately adjust the strength of magnetic field of theMNG resonator 800. The impedance of theMNG resonator 800 may be determined by thematcher 830. In one or more embodiments, current may flow in theMNG resonator 800 via aconnector 840, or may flow out from theMNG resonator 800 via theconnector 840. And theconnector 840 may be connected to theground conducting portion 813 or thematcher 830. - As shown in
FIG. 8 , thematcher 830 may be positioned within the loop formed by the loop structure of theresonator 800. Thematcher 830 may be configured to adjust the impedance of theresonator 800 by changing the physical shape of thematcher 830. For example, thematcher 830 may include theconductor 831 for the impedance-matching in a location separate from theground conducting portion 813 by a distance h. The impedance of theresonator 800 may be changed by adjusting the distance h. - In some implementations, a controller may be provided to control the
matcher 830. In this case, thematcher 830 may change the physical shape of thematcher 830 based on a control signal generated by the controller. For example, the distance h between theconductor 831 of thematcher 830 and theground conducting portion 813 may be increased or decreased based on the control signal. Accordingly, the physical shape of thematcher 830 may be changed such that the impedance of theresonator 800 may be adjusted. The distance h between theconductor 831 of thematcher 830 and theground conducting portion 813 may be adjusted using a variety of schemes. For example, a plurality of conductors may be included in thematcher 830 and the distance h may be adjusted by adaptively activating one of the conductors. Alternatively or additionally, the distance h may be adjusted by adjusting the physical location of theconductor 831 up and down. For instance, the distance h may be controlled based on the control signal of the controller. The controller may generate the control signal using various factors. As shown inFIG. 8 , thematcher 830 may be configured as a passive element such as theconductor 831, for instance. Of course, in other embodiments, thematcher 830 may be configured as an active element such as, for example, a diode, a transistor, or the like. When the active element is included in thematcher 830, the active element may be driven based on the control signal generated by the controller, and the impedance of theresonator 800 may be adjusted based on the control signal. For example, if the active element is a diode included in thematcher 830, the impedance of theresonator 800 may be adjusted depending on whether the diode is in an ON state or in an OFF state. - In some implementations, a magnetic core may be further provided to pass through the
resonator 800 configured as the MNG resonator. The magnetic core may perform a function of increasing a power transmission distance. -
FIG. 9 illustrates aresonator 900 for a wireless power transmission configured as a bulky type. - As used herein, the term “bulky type” may refer to a seamless connection connecting at least two parts in an integrated form.
- Referring to
FIG. 9 , a first signal conducting portion 911 and aconductor 942 may be integrally formed instead of being separately manufactured and thereby be connected to each other. Similarly, the second signal conducting portion 912 and aconductor 941 may also be integrally manufactured. - When the second signal conducting portion 912 and the
conductor 941 are separately manufactured and then are connected to each other, a loss of conduction may occur due to aseam 950. Thus, in some implementations, the second signal conducting portion 912 and theconductor 941 may be connected to each other without using a separate seam, (i.e., seamlessly connected to each other). Accordingly, it is possible to decrease a conductor loss caused by theseam 950. For instance, the second signal conducting portion 912 and aground conducting portion 913 may be seamlessly and integrally manufactured. Similarly, the first signal conducting portion 911, theconductor 942 and theground conducting portion 913 may be seamlessly and integrally manufactured. - A
matcher 930 may be provided that is similarly constructed as described herein in one or more embodiments.FIG. 10 illustrates aresonator 1000 for a wireless power transmission, configured as a hollow type. - Referring to
FIG. 10 , each of a firstsignal conducting portion 1011, a second signal conducting portion 1012, a ground conducting portion 1013, andconductors resonator 1000 configured as the hollow type structure. As used herein the term “hollow type” refers to a configuration that may include an empty space inside. - For a given resonance frequency, an active current may be modeled to flow in only a portion of the first
signal conducting portion 1011 instead of all of the firstsignal conducting portion 1011, the second signal conducting portion 1012 instead of all of the second signal conducting portion 1012, the ground conducting portion 1013 instead of all of the ground conducting portion 1013, and theconductors conductors signal conducting portion 1011, the second signal conducting portion 1012, the ground conducting portion 1013, and theconductors resonator 1000 in some instances. - Accordingly, for the given resonance frequency, the depth of each of the first
signal conducting portion 1011, the second signal conducting portion 1012, the ground conducting portion 1013, and theconductors signal conducting portion 1011, the second signal conducting portion 1012, the ground conducting portion 1013, and theconductors signal conducting portion 1011, the second signal conducting portion 1012, the ground conducting portion 1013, and theconductors resonator 1000 may become light, and manufacturing costs of theresonator 1000 may also decrease. - For example, as shown in
FIG. 10 , the depth of the second signal conducting portion 1012 (as further illustrated in the enlarged view region 1060 indicated by a circle) may be determined as “d” mm and d may be determined according to -
- Here, f denotes a frequency, μ denotes a magnetic permeability, and σ denotes a conductor constant. In one implementation, when the first
signal conducting portion 1011, the second signal conducting portion 1012, the ground conducting portion 1013, and theconductors - A
capacitor 1020 and amatcher 1030 may be provided that are similarly constructed as described herein in one or more embodiments. -
FIG. 11 illustrates aresonator 1100 for a wireless power transmission using a parallel-sheet. - Referring to
FIG. 11 , the parallel-sheet may be applicable to each of a firstsignal conducting portion 1111 and a second signal conducting portion 1112 included in theresonator 1100. - Each of the first
signal conducting portion 1111 and the second signal conducting portion 1112 may not be a perfect conductor and thus, may have an inherent resistance. Due to this resistance, an ohmic loss may occur. The ohmic loss may decrease a Q-factor and also decrease a coupling effect. - By applying the parallel-sheet to each of the first
signal conducting portion 1111 and the second signal conducting portion 1112, it may be possible to decrease the ohmic loss, and to increase the Q-factor and the coupling effect. Referring to theenlarged view portion 1170 indicated by a circle, when the parallel-sheet is applied, each of the firstsignal conducting portion 1111 and the second signal conducting portion 1112 may include a plurality of conductor lines. The plurality of conductor lines may be disposed in parallel, and may be electrically connected (i.e., shorted) at an end portion of each of the firstsignal conducting portion 1111 and the second signal conducting portion 1112. - When the parallel-sheet is applied to each of the first
signal conducting portion 1111 and the second signal conducting portion 1112, the plurality of conductor lines may be disposed in parallel. Accordingly, a sum of resistances having the conductor lines may decrease. Consequently, the resistance loss may decrease, and the Q-factor and the coupling effect may increase. - A
capacitor 1120 and a matcher 1130 positioned on theground conducting portion 1113 may be provided that are similarly constructed as described herein in one or more embodiments.FIG. 12 illustrates aresonator 1200 for a wireless power transmission, including a distributed capacitor. - Referring to
FIG. 12 , acapacitor 1220 included in theresonator 1200 is configured for the wireless power transmission. A capacitor used as a lumped element may have a relatively high equivalent series resistance (ESR). A variety of schemes have been proposed to decrease the ESR contained in the capacitor of the lumped element. According to an embodiment, by using thecapacitor 1220 as a distributed element, it may be possible to decrease the ESR. As will be appreciated, a loss caused by the ESR may decrease a Q-factor and a coupling effect. - As shown in
FIG. 12 , thecapacitor 1220 may be configured as a conductive line having the zigzagged structure. - By employing the
capacitor 1220 as the distributed element, it may be possible to decrease the loss occurring due to the ESR in some instances. In addition, by disposing a plurality of capacitors as lumped elements, it is possible to decrease the loss occurring due to the ESR. Since a resistance of each of the capacitors as the lumped elements decreases through a parallel connection, active resistances of parallel-connected capacitors as the lumped elements may also decrease whereby the loss occurring due to the ESR may decrease. For example, by employing ten capacitors of 1 pF each instead of using a single capacitor of 10 pF, it may be possible to decrease the loss occurring due to the ESR in some instances. -
FIG. 13A illustrates one embodiment of thematcher 730 used in theresonator 700 provided in the 2D structure ofFIG. 7 , andFIG. 13B illustrates an example of thematcher 830 used in theresonator 800 provided in the 3D structure ofFIG. 8 . -
FIG. 13A illustrates a portion of the 2D resonator including thematcher 730, andFIG. 13B illustrates a portion of the 3D resonator ofFIG. 8 including thematcher 830. - Referring to
FIG. 13A , thematcher 730 may include theconductor 731, aconductor 732, and aconductor 733. Theconductors ground conducting portion 713 and theconductor 731. The impedance of the 2D resonator may be determined based on a distance h between theconductor 731 and theground conducting portion 713. The distance h between theconductor 731 and theground conducting portion 713 may be controlled by the controller. The distance h between theconductor 731 and theground conducting portion 713 can be adjusted using a variety of schemes. For example, the variety of schemes may include, for instance, one or more of the following: a scheme of adjusting the distance h by adaptively activating one of theconductors conductor 731 up and down, and/or the like. - Referring to
FIG. 13B , thematcher 830 may include theconductor 831, aconductor 832, aconductor 833 andconductors conductors ground conducting portion 813 and theconductor 831. Also, theconductors ground conducting portion 813. The impedance of the 3D resonator may be determined based on a distance h between theconductor 831 and theground conducting portion 813. The distance h between theconductor 831 and theground conducting portion 813 may be controlled by the controller, for example. Similar to thematcher 730 included in the 2D structured resonator, in thematcher 830 included in the 3D structured resonator, the distance h between theconductor 831 and theground conducting portion 813 may be adjusted using a variety of schemes. For example, the variety of schemes may include, for instance, one or more of the following: a scheme of adjusting the distance h by adaptively activating one of theconductors conductor 831 up and down, or the like. - In some implementations, the matcher may include an active element. Thus, a scheme of adjusting an impedance of a resonator using the active element may be similar as described above. For example, the impedance of the resonator may be adjusted by changing a path of a current flowing through the matcher using the active element.
-
FIG. 14 illustrates one equivalent circuit of theresonator 700 for the wireless power transmission ofFIG. 7 . - The
resonator 700 ofFIG. 7 for the wireless power transmission may be modeled to the equivalent circuit ofFIG. 14 . In the equivalent circuit depicted inFIG. 14 , LR denotes an inductance of the power transmission line, CL denotes thecapacitor 720 that is inserted in a form of a lumped element in the middle of the power transmission line, and CR denotes a capacitance between the power transmissions and/or ground ofFIG. 7 . - In some instances, the
resonator 700 may have a zeroth resonance characteristic. For example, when a propagation constant is “0”, theresonator 700 may be assumed to have ωMZR as a resonance frequency. The resonance frequency ωMZR may be expressed by Equation 2. -
- In Equation 2, MZR denotes a Mu zero resonator.
- Referring to Equation 2, the resonance frequency ωMZR of the
resonator 700 may be determined by -
- A physical size of the
resonator 700 and the resonance frequency ωMZR may be independent with respect to each other. Since the physical sizes are independent with respect to each other, the physical size of theresonator 700 may be sufficiently reduced. - According to one or more embodiments, there may be provided a DC/DC converter that may detect an amount of current of a DC/DC converter without directly sensing the amount of current of the DC/DC converter, and may control a turn-on period of a turn-on switch based on detected amount of current. When the amount of current is low, the DC/DC converter may decrease the turn-on period to reduce a switching loss.
- One or more of the above-described embodiments may be recorded in non-transitory computer-readable media including program instructions to implement various operations embodied by a computer. The media may also include, alone or in combination with the program instructions, data files, data structures, and the like. Examples of non-transitory computer-readable media include magnetic media such as hard disks, floppy disks, and magnetic tape; optical media such as CD ROM discs and DVDs; magneto-optical media such as optical discs; and hardware devices that are specially configured to store and perform program instructions, such as read-only memory (ROM), random access memory (RAM), flash memory, and the like. Examples of program instructions include both machine code, such as produced by a compiler, and files containing higher level code that may be executed by the computer using an interpreter. The described hardware devices may be configured to act as one or more software modules in order to perform the operations of the above-described example embodiments, or vice versa. In addition, a non-transitory computer-readable storage medium may be distributed among computer systems connected through a network and non-transitory computer-readable codes or program instructions may be stored and executed in a decentralized manner.
- A number of example embodiments have been described above. Nevertheless, it should be understood that various modifications may be made. For example, suitable results may be achieved if the described techniques are performed in a different order and/or if components in a described system, architecture, device, or circuit are combined in a different manner and/or replaced or supplemented by other components or their equivalents. Accordingly, other implementations are within the scope of the following claims.
Claims (17)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1020100130861A KR20120069349A (en) | 2010-12-20 | 2010-12-20 | Dc-dc converter for reducing switching loss, wireless power receiving apparatus including the dc-dc converter |
KR10-2010-0130861 | 2010-12-20 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20120155133A1 true US20120155133A1 (en) | 2012-06-21 |
Family
ID=46234188
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/329,891 Abandoned US20120155133A1 (en) | 2010-12-20 | 2011-12-19 | Direct current/ direct current converter for reducing switching loss, wireless power receiver including direct current/ direct current converter |
Country Status (6)
Country | Link |
---|---|
US (1) | US20120155133A1 (en) |
EP (1) | EP2656478A4 (en) |
JP (1) | JP2014501477A (en) |
KR (1) | KR20120069349A (en) |
CN (1) | CN103283118A (en) |
WO (1) | WO2012086975A2 (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20120217820A1 (en) * | 2009-07-06 | 2012-08-30 | Young Tack Hong | Wireless power transmission system and resonator for the system |
US20150214825A1 (en) * | 2014-01-30 | 2015-07-30 | Silicon Laboratories Inc. | Pseudo-constant frequency control for voltage converter |
US20170104373A1 (en) * | 2012-02-21 | 2017-04-13 | Lg Innotek Co., Ltd. | Wireless power transmitter and method of managing thereof |
US20170201126A1 (en) * | 2016-01-11 | 2017-07-13 | Electronics And Telecommunications Research Institute | Apparatus and method for receiving wireless power, and system for transmitting wireless power |
WO2019043514A1 (en) * | 2017-09-01 | 2019-03-07 | 3M Innovative Properties Company | Wireless power transfer and sensing for monitoring pipelines |
WO2020085866A1 (en) * | 2018-10-26 | 2020-04-30 | Samsung Electronics Co., Ltd. | Electronic device and method for controlling recharge of battery |
US20210172981A1 (en) * | 2020-11-02 | 2021-06-10 | Fu Da Tong Technology Co., Ltd. | Signal analysis circuit and method |
US11218077B2 (en) | 2014-01-30 | 2022-01-04 | Skyworks Solutions, Inc. | Soft-start for isolated power converter |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR102096092B1 (en) * | 2012-10-30 | 2020-04-02 | 삼성디스플레이 주식회사 | Dc-dc converter and organic light emitting display device using the same |
JP6075089B2 (en) * | 2013-01-31 | 2017-02-08 | ミツミ電機株式会社 | Switching power supply circuit, switching power supply device |
KR102032560B1 (en) | 2013-02-05 | 2019-10-15 | 지이 하이브리드 테크놀로지스, 엘엘씨 | Wireless power receiving apparatus for low heat and method thereof |
KR102257633B1 (en) * | 2013-02-05 | 2021-06-01 | 지이 하이브리드 테크놀로지스, 엘엘씨 | Wireless power receiving apparatus for low heat and method thereof |
KR20150062785A (en) * | 2013-11-29 | 2015-06-08 | 주식회사 한림포스텍 | Low heat wireless power receiving device |
CN106134032B (en) | 2014-03-27 | 2018-12-25 | Lg伊诺特有限公司 | Wireless power transmission system with wireless power sending device |
JP6348854B2 (en) * | 2015-02-03 | 2018-06-27 | 富士フイルム株式会社 | Endoscope processor device, endoscope system, and non-contact power feeding method for endoscope system |
KR102425702B1 (en) * | 2019-10-08 | 2022-07-29 | 지이 하이브리드 테크놀로지스, 엘엘씨 | Wireless power receiving apparatus for low heat and method thereof |
KR20200125915A (en) * | 2020-10-23 | 2020-11-05 | 지이 하이브리드 테크놀로지스, 엘엘씨 | Low heat wireless power receiving device |
KR102420250B1 (en) * | 2020-12-24 | 2022-07-14 | 한국전자기술연구원 | Receiver and method for wireless power transmission with input impedance compensation of rectifier applied |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040232901A1 (en) * | 2003-05-19 | 2004-11-25 | Kent Huang | Delta-sigma DC-to-DC converter and method thereof |
US20050057228A1 (en) * | 2003-09-15 | 2005-03-17 | Semiconductor Components Industries, Llc | Method and circuit for optimizing power efficiency in a DC-DC converter |
US20060043955A1 (en) * | 2004-08-26 | 2006-03-02 | Huan-Jan Hung | PWM controller for a voltage regulator |
US7145317B1 (en) * | 2004-12-13 | 2006-12-05 | Intersil Americas Inc. | Constant frequency duty cycle independent synthetic ripple regulator |
US20090302911A1 (en) * | 2008-06-06 | 2009-12-10 | Niko Semiconductor Co., Ltd. | Frequency jitter generator and pwm controller |
US7812580B2 (en) * | 2005-05-26 | 2010-10-12 | Rohm Co., Ltd. | Power supply apparatus having switchable switching regulator and linear regulator |
US20100277003A1 (en) * | 2009-03-20 | 2010-11-04 | Qualcomm Incorporated | Adaptive impedance tuning in wireless power transmission |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE69623683T2 (en) * | 1995-04-27 | 2003-08-07 | Fluke Corp | Delta-T measurement circuit |
US7215107B2 (en) * | 2005-07-11 | 2007-05-08 | Power Integrations, Inc. | Method and apparatus to limit output power in a switching power supply |
JP2007151248A (en) * | 2005-11-25 | 2007-06-14 | Mitsumi Electric Co Ltd | Multi-output type dc-dc converter |
JP4850540B2 (en) * | 2005-12-26 | 2012-01-11 | 富士通セミコンダクター株式会社 | DC-DC converter and control circuit for DC-DC converter |
KR100764779B1 (en) * | 2006-03-14 | 2007-10-11 | 엘지전자 주식회사 | Apparatus for supplying dc power source |
JP4807142B2 (en) * | 2006-05-25 | 2011-11-02 | 株式会社豊田自動織機 | DC / DC converter |
US7471530B2 (en) * | 2006-10-04 | 2008-12-30 | Power Integrations, Inc. | Method and apparatus to reduce audio frequencies in a switching power supply |
JP2008228417A (en) * | 2007-03-12 | 2008-09-25 | Matsushita Electric Ind Co Ltd | Dc-dc converter |
US7719251B2 (en) * | 2007-08-06 | 2010-05-18 | Intel Corporation | Enhancement of power conversion efficiency using dynamic load detecting and tracking |
US8129864B2 (en) * | 2008-01-07 | 2012-03-06 | Access Business Group International Llc | Inductive power supply with duty cycle control |
US8855554B2 (en) * | 2008-03-05 | 2014-10-07 | Qualcomm Incorporated | Packaging and details of a wireless power device |
-
2010
- 2010-12-20 KR KR1020100130861A patent/KR20120069349A/en not_active Application Discontinuation
-
2011
- 2011-12-19 EP EP11850511.4A patent/EP2656478A4/en not_active Withdrawn
- 2011-12-19 CN CN2011800615956A patent/CN103283118A/en active Pending
- 2011-12-19 JP JP2013544404A patent/JP2014501477A/en not_active Withdrawn
- 2011-12-19 US US13/329,891 patent/US20120155133A1/en not_active Abandoned
- 2011-12-19 WO PCT/KR2011/009767 patent/WO2012086975A2/en active Application Filing
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040232901A1 (en) * | 2003-05-19 | 2004-11-25 | Kent Huang | Delta-sigma DC-to-DC converter and method thereof |
US20050057228A1 (en) * | 2003-09-15 | 2005-03-17 | Semiconductor Components Industries, Llc | Method and circuit for optimizing power efficiency in a DC-DC converter |
US20060043955A1 (en) * | 2004-08-26 | 2006-03-02 | Huan-Jan Hung | PWM controller for a voltage regulator |
US7145317B1 (en) * | 2004-12-13 | 2006-12-05 | Intersil Americas Inc. | Constant frequency duty cycle independent synthetic ripple regulator |
US7812580B2 (en) * | 2005-05-26 | 2010-10-12 | Rohm Co., Ltd. | Power supply apparatus having switchable switching regulator and linear regulator |
US20090302911A1 (en) * | 2008-06-06 | 2009-12-10 | Niko Semiconductor Co., Ltd. | Frequency jitter generator and pwm controller |
US20100277003A1 (en) * | 2009-03-20 | 2010-11-04 | Qualcomm Incorporated | Adaptive impedance tuning in wireless power transmission |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20120217820A1 (en) * | 2009-07-06 | 2012-08-30 | Young Tack Hong | Wireless power transmission system and resonator for the system |
US20170104373A1 (en) * | 2012-02-21 | 2017-04-13 | Lg Innotek Co., Ltd. | Wireless power transmitter and method of managing thereof |
US20150214825A1 (en) * | 2014-01-30 | 2015-07-30 | Silicon Laboratories Inc. | Pseudo-constant frequency control for voltage converter |
US9531284B2 (en) * | 2014-01-30 | 2016-12-27 | Silicon Laboratories Inc. | Pseudo-constant frequency control for voltage converter |
US11218077B2 (en) | 2014-01-30 | 2022-01-04 | Skyworks Solutions, Inc. | Soft-start for isolated power converter |
US10298066B2 (en) * | 2016-01-11 | 2019-05-21 | Electronics And Telecommunications Research Institute | Apparatus and method for receiving wireless power, and system for transmitting wireless power |
US20170201126A1 (en) * | 2016-01-11 | 2017-07-13 | Electronics And Telecommunications Research Institute | Apparatus and method for receiving wireless power, and system for transmitting wireless power |
WO2019043514A1 (en) * | 2017-09-01 | 2019-03-07 | 3M Innovative Properties Company | Wireless power transfer and sensing for monitoring pipelines |
US10823717B2 (en) | 2017-09-01 | 2020-11-03 | 3M Innovative Properties Company | Wireless power transfer and sensing for monitoring pipelines |
WO2020085866A1 (en) * | 2018-10-26 | 2020-04-30 | Samsung Electronics Co., Ltd. | Electronic device and method for controlling recharge of battery |
US11177681B2 (en) | 2018-10-26 | 2021-11-16 | Samsung Electronics Co., Ltd. | Electronic device and method for controlling recharge of battery |
US20210172981A1 (en) * | 2020-11-02 | 2021-06-10 | Fu Da Tong Technology Co., Ltd. | Signal analysis circuit and method |
US11733328B2 (en) * | 2020-11-02 | 2023-08-22 | Fu Da Tong Technology Co., Ltd. | Signal analysis circuit and method |
Also Published As
Publication number | Publication date |
---|---|
EP2656478A4 (en) | 2014-08-20 |
EP2656478A2 (en) | 2013-10-30 |
KR20120069349A (en) | 2012-06-28 |
WO2012086975A3 (en) | 2012-08-23 |
CN103283118A (en) | 2013-09-04 |
WO2012086975A2 (en) | 2012-06-28 |
JP2014501477A (en) | 2014-01-20 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20120155133A1 (en) | Direct current/ direct current converter for reducing switching loss, wireless power receiver including direct current/ direct current converter | |
US9711968B2 (en) | Wireless power transmission apparatus and wireless power transmission method | |
US10224754B2 (en) | Wireless power transmission and charging system, and resonance frequency control method of wireless power transmission and charging system | |
US9431889B2 (en) | Active rectifier with delay locked loop to compensate for reverse current leakage and wireless power receiving apparatus including active rectifier with delay locked loop to compensate for reverse current leakage | |
US9484737B2 (en) | Protector of rectifier and wireless power receiver including protector | |
US10749378B2 (en) | Resonance power transmission system based on power transmission efficiency | |
US9509173B2 (en) | Wireless power transmission and charging system, and impedance control method thereof | |
US9787105B2 (en) | Apparatus and method for high efficiency variable power transmission | |
US9496718B2 (en) | Wireless power transmission system, and method of controlling resonance impedance and resonance frequency of wireless power transmission system | |
US10103785B2 (en) | Apparatus and method for resonance power transmission and resonance power reception | |
US8704534B2 (en) | Method and apparatus of tracking of resonant impedance in resonance power transfer system | |
US9088167B2 (en) | Wireless power transmission system using solar cell module | |
US9276433B2 (en) | Robot cleaning system and control method having a wireless electric power charge function | |
US8368471B2 (en) | Resonance power generator | |
US9124115B2 (en) | High efficiency rectifier, wireless power receiver including the rectifier | |
US9692486B2 (en) | System for wireless power transmission and reception | |
US9178388B2 (en) | Wireless power transmission apparatus | |
US20110241613A1 (en) | Wireless power receiving apparatus including a shielding film | |
US8957630B2 (en) | Reflected energy management apparatus and method for resonance power transmission | |
US8890367B2 (en) | Resonance power receiver that includes a plurality of resonators |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: SAMSUNG ELECTRONICS CO., LTD., KOREA, REPUBLIC OF Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KIM, DONG ZO;HONG, YOUNG TACK;MOON, YOUNG JIN;AND OTHERS;REEL/FRAME:027410/0074 Effective date: 20111219 Owner name: IUCF-HYU (INDUSTRY-UNIVERSITY COOPERATION FOUNDATI Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KIM, DONG ZO;HONG, YOUNG TACK;MOON, YOUNG JIN;AND OTHERS;REEL/FRAME:027410/0074 Effective date: 20111219 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |